Clinical catheterization technique and apparatus for performing same

ABSTRACT

An improved clinical technique for central venous catheterization and apparatus for performing same. The catheterization apparatus includes a small gauge hollow steel needle having a long plastic catheter introducer covering all but the very tip of the needle. The needle positions the plastic introducer into the vein whereupon the needle is removed. Next, a guide wire is inserted into the introducer and into the vein. After the guide wire is in place, the introducer is peeled away from the guide wire, and the guide wire and plastic catheter are threaded into the central venous system. Once the catheter is in place, the guide wire is removed, the catheter is attached to an intravenous unit and the catheter is sutured to the skin.

This application is a continuation of my U.S. patent application, Ser.No. 647,930, filed Sept. 6, 1984.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates generally to an improved clinicaltechnique for catheterization and apparatus for performing same, andmore particularly, an improved technique for central venouscatheterization.

The sole objective of central venous catheterization is to establish adirect conduit from the exterior of the body to the superior vena cava.Thus, catheterization of the superior cava is invaluable in specialcircumstances when there is critical necessity to: (1) measure centralvenous pressure frequently to guide fluid balance endeavors in personswith marginal cardiac or renal reserve; (2) procure aliquots of mixedvenous blood repeatedly for gasometric or biochemical analysis; (3)administer massive volumes of fluids or blood rapidly for resuscitationand ancillary purposes; and (4) infuse intravenously, over long periodsof time, hypertonic, acidic, or kindred irritant solutions which wouldassuredly incite phlebosclerosis were they not diluted right away in thefaster stream of central venous channels.

Traditionally, central venous catheterization has been saved as a lastresort when other routes were non-existent at the outset or becameexhausted. It has been considered preferable to try a safer procedurebefore using one that carried risks. However, the benefits of using acentral insertion site may outweigh the risk because the central venousvein: (1) is closer to the cava; (2) has a constant location; (3) isrelatively big; (4) has a fairly large volume flow through it; (5) isless liable to collapse or go into spasm, being kept patulous by fibrousattachments from its walls to adjacent rigid structures; (6) rarely isanomalous or diseased; and (7) is sheltered by the clavicle fromordinary external trauma.

Several techniqes have been developed in the past in an attempt toreduce the risks associated with central venous catheterization. Onesuch attempt is the "through the needle" technique for catheterizationwhereby the patient is first placed in the trendelenburg position(supine with feed higher than head). Then, the skin over and around thesubclavian vein is cleaned with antiseptic solution and a sterile fieldor working area is set-up using sterile towels. A small area of skin(the proposed puncture site) within the sterile field is thenanesthetized by injecting a small amount of local anesthetic into theskin using a small hollow needle and syringe. Next, a large (14 gauge 7cm long) hollow needle with a syringe is passed through the anesthetizedskin and into the vein. After puncturing the skin, continuous suction isapplied to the syringe. By applying continuous suction, entrance intothe subclavian vein is signaled by the appearance of blood into theattached syringe. Once the needle is in position, the syringe is removedfrom the needle and a smaller diameter catheter (16 gauge flexiblehollow tube about 50 cm long) is passed through the needle along thecourse of the vein and into the central venous system (superior venacava). The needle is then withdrawn over the catheter, leaving thecatheter in the puncture site.

There are several distinct disadvantages associated with the utilizationof the through the needle catheterization technique. First, because alarge needle must be used, there is an increased chance of pneumothoraxif the pleura cavity is punctured and a greater chance of air emboluswhen the syringe is removed from the needle to insert the catheter. Inaddition, because the needle is larger than the catheter, the puncturewound is not sealed completely by the catheter, increasing the chance ofthe ingress of air (air embolus) and seepage of blood (hematomaformation) around the catheter. Furthermore, the larger needle thegreater the chance of hemorrhage if the subclavian artery is punctured.Because the catheter must pass over the sharp edge of the needle, thetip of the catheter may be seared off into the blood stream causingembolus. Lastly, because the catheter is flexible, it is hard to directit into the right position during insertion and my have a tendency tobuckle or kink when it meets resistance, especially when turningcorners. Thus, there has been a need for an improved catheterizationtechnique and apparatus for performing same which overcomes thesedisadvantages while providing an improved technique as compared to priorconventional techniques.

Alternatively, it is conventional to use an "over the wire"catheterization technique. As with the through the needlecatheterization technique, the patient is prepared as set forth above.However, a larger (16 gauge 7 cm long) hollow needle with a syringeattached is passed through the anesthetized skin and into the subclavianvein. After puncturing the skin, continuous suction is applied to thesyringe the appearance of blood signals entrance into the vein. Next,the syringe is taken off the needle and a long 70 cm guide wire, with afloppy tip and a diameter about equal to the internal diameter of theneedle, is passed through the needle, floppy end first, into the vein.The needle is then withdrawn from the patient over the guide wire and along 50 cm 16 gauge hollow catheter is threaded onto the wire. Next, thewire and the catheter are passed along the inside of the subclavian veininto the central venous system (superior vena cava).

There is a distinct disadvantage associated with the utilization of theabove mentioned over the wire catheterization technique, namely that thetechnique is substantially slower than the through the needle technique.First, the guide wire must be threaded through the needle into thesubclavian vein and then the needle removed. Next, the catheter must bethreaded onto the wire, and then both are threaded inside of the veininto the central venous system. Finally, after all of the above, thewire is removed. All these steps require substantial time, which may beunavailable and time is of vital importance in an emerency situation.Thus, there has been a need for an improved catheterization techniquewhich overcomes these disadvantages while providing an improvedtechnique as compared to prior techniques.

The present invention is directed to an improved clinicalcatheterization technique and apparatus for performing same which issuperior to conventional methods of central venous catheterization andwhich offers a combination of quick application, better control ofcatheter positioning and decreased chances of air embolus, hemorrhage,hematoma formation, catheter embolus and pheumothorax.

SUMMARY OF THE INVENTION

The present invention provides an improved clinical technique andapparatus for catheterization. Specifically, according to the principlesof the present invention the patient is prepared using conventionaltechniques. Namely, the patient is first placed in the trendelenburgposition (supine with feet higher than head). Next, the skin over andaround the subclavian vein is cleaned with antiseptic solution, and asterile field of working area is set-up using sterile towels. A smallarea of the skin (the proposed puncture site) is then anesthetized byinjecting a small amount of local anesthetic into the skin using a smallhollow needle and syringe. According to the principles of the presentinvention, after preparing the patient and the proposed puncture site, asmall steel needle is passed through the anesthetized skin and into thesubclavin vein. A small flexible, tubular catheter introducer, slitlengthwise from tip through base, covers all but the exposed tip of thesteel needle. After puncturing the skin, continuous suction is appliedto a syringe attached to the steel needle. Entrance into the vein issignaled by the appearance of blood in the syringe. The small introduceris then pushed further into the vein and the needle is removed. Anexposed floppy tip of a guide wire with a plastic catheter attached toits other end, is then passed through the small catheter introducer sothat the tip of the guide wire is in the vein. Then, the smallpreviously slit introducer is pulled out of the vein and skin. Theintroducer is then peeled away from the guide wire, through the slit.The exposed portion of the guide wire and plastic catheter assembly arethen threaded into the central venous system. After properly positioningthe plastic catheter and guide wire, the guide wire is removed throughthe catheter and the catheter is attached to an intravenous set andsutured to the skin.

The improved catheterization technique provides several advantages overconventional techniques and reduces several of the risks associatedtherewith. Specifically, the improved technique and apparatus allows forthe positioning of the catheter more easily and quickly. The smallneedle decreases the chance of pneumothorax if the pleura is puncturedand decreases the chances of air embolus when the syringe is removed toinsert the guide wire. In addition, the smaller needle decreases thechange of hemorrhage if the artery is puncture. Further, because thepuncture site more closely matches the catheter, a better seal isprovided when the catheter is placed in position to decrease the chanceof the ingress of air or air embolus, and the seepage of blood or theformation of hematoma are decreased.

The improved clinical catheterization technique and apparatus forperforming same provides an improved means for the infusion of fluidsinto circulatory system following trauma, pathological fluid loss, orthe like, that is uncomplicated and inexpensive to manufacture and use.

DESCRIPTION OF THE DRAWINGS

Various objects, benefits, and advantages of the present invention willbecome more apparent upon reading the following detailed description inconjunction with the drawings where like reference numerals identifycorresponding components:

FIG. 1 is a side view of the central venous catheterization apparatus ofthe present invention showing the guide wire and catheter of the presentinvention;

FIG. 2 is a side view of the needle, syringe and introducer of thepresent invention;

FIG. 3 is an enlarged side view, partially cross-sectioned, of theneedle and introducer;

FIG. 4 is a schematic side view of a patient showing insertion of theneedle and introducer into the puncture site and subclavian vein;

FIG. 5 is a schematic side view of a patient similar to FIG. 4 showingthe insertion of the guide wire; and

FIG. 6 is a side view of the introducer of the present invention beingpeeled away from the guide wire.

DETAIL DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2 of the drawings, the improved clinicalcatheterization technique and apparatus for central venouscatheterization is illustrated. The catheterization apparatus includes asyringe 12, hollow needle 14, plastic sheath or catheter introducer 16,guide wire 18, and catheter 20.

Referring now to FIGS. 2 and 3, hollow needle 14 is attached to syringe12, and sheath or flexible tubular introducer 16 covers shaft portion 21of needle 14 to adjacent tip 22. A slit 24 extends longitudinally theentire length of introducer 16 parallel to the central axis of needle14. Introducer 16 has a frustoconical end portion 25. The particularmaterial of which needle 14 is made is not essential to the presentinvention. The needle is a trocar to pierce and transverse tissue beforepenetrating the vein with its tip which is sharp and slanted. A suitablematerial is 16 to 20 gauge steel tubing which provides rigidity and easysterilization.

Referring again to FIG. 1, guide wire 18 and plastic catheter 20 may betelescopically receivable and may be attached whereby exposed portion 30of guide wire 18 partially extends from catheter 20. Guide wire 18 mayfit snugly into catheter 20 or may be accommodated by a dialator (notshown). Guide wire 18 has an exposed floppy tip or J-shaped tip 32 toheld end 32 of guide wire 18 to remain central while being inserted intothe central venous system, instead of catching in the venous walls andpuncturing the vein, or curling. Therefore, the soft-tip wires are goodfor use in almost all veins and almost all circumstances. However,running a stiff tip through needle 14 into the vein can be dangerousbecause it can penetrate through the vein into the underlayingstructure.

In the illustrated embodiment, for central venous subclaviancatheterization, exposed potion 30 of guide wire 18 is approximately 20cm in length with guide wire 18 having a total length of approximately70 cm. Portion 30 is capable of passing through a plastic sheath orcatheter introducer 16 for positioning catheter 20 within the subclavinvein. In addition, catheter 20 is approximately 50 cm long of 16 gaugeplastic tubing. Because catheter 20 has to negotiate curvatures on itsway and float freely without hurting the vein lining, it should beflexible and smooth tipped. For example, catheter 20 and introducer 16may be constructed of a tubular material such as silicone elastomer,teflon, polyethylene or the like. The softer and more pliable the tubingthe more likely it will glance off the vein wall without perforating thelater.

As is disclosed, a knob 34 is fixably attached to guide wire 36 for easyremoval upon properly positioning catheter 20 within the subclavianvein.

Clinical Method and Use

The operation and use of the present improved catheterization techniquemay now be explained. The patient is first placed in the trendelenburgposition (supine with feet above the level of the head) in a manner wellknown in the medical art, by laying the patient flat on his back,unpropped on bolsters, shoulders relaxed and neither hunched norshrugged. The upper half of the patient's body should be tilted down 15to 30 degrees from the horizontal, arms straight alongside the trunk orhands crossed over the abdomen, and the face turned slightly away fromthe operating site. Next, the skin over and around the subclavian vein40 is cleansed with an antiseptic solution. A sterile field or workingarea is then setup using sterile towels. A small area of skin at theproposed puncture site 42 is then anesthetized by injecting a smallamount of local anesthetic into the skin. As shown in FIG. 4, needle 14and introducer 16 are both passed through the anesthetized skin 42 andinto the subclavian vein 40.

After puncturing the skin, continuous suction is applied to syringe 12attached to needle 14. It is very important that the user aspiratecontinuously as he advances needle 14 so that entrance into thesubclavian vein 12 is signaled by the appearance of blood in thesyringe. Many times blood will not flash back unless a syringe isattached to the needle because pressure in the vein is low. In addition,it is very easy to go all the way through the vein without realizing it,especially if needle 14 is inserted during inspiration, when the veinmay be more collapsed. The plastic sheath or introducer 16 is thenpushed further into the subclavian vein 40 and syringe 12 and needle 14are removed.

As illustrated in FIG. 5, the exposed floppy tip 32 of guide wire 18 isthen threaded into introducer 16 so that the tip of the guide wire is inthe subclavian vein. It is imperative that guide wire 18 not be forced,but it should literally "float" right in. Then, introducer 16 is pulledout of the subclavian vein and skin 42 along the exposed portion ofguide wire 18. Next introducer 16 is peeled away from the guide wirethrough slit 24, FIG. 6. The slit makes this maneuver possible. Catheter20 and guide wire 18 are then threaded into the central venous system.The catheter will be forced to follow along the route of the guide wireand therefore go into the vein. Next, after properly positioningcatheter 20, guide wire 18 is removed by pulling on knob 34 which isattached to guide wire 18.

After the guide wire is removed, catheter 20 can then be attached to anintravenous apparatus and sutured to the skin in a manner well known inthe art. For example, the catheter may be anchored to the skin by3-point fixation with non-absorbable suture. Stiches may warp or brakeplastic catheter 20, so strips of sterile paper adhesive tape orcatheter guard may be wrapped around the section of the catheter to betied. Alternatively, catheter 20 may be sutured to the patient's skin bytab 36.

The present catheterization technique described can be used with any ofthe current methods and techniques of central venous catheterizationsuch as femoral vein, internal jugular vein, external jugular vein,supraclavicular subclavian vein and surgical cut down. Perecutaneoussubclavian central venous catheterization means to pass a hollowflexible tube such as catheter 20 through the skin, under the clavicle,into and then along the inside of the subclavian vein into the centralvenous system. This is invaluable in special circumstances when there isa critical necessity to: (1) measure central venous pressure frequentlyto guide fluid balance endeavors in persons with marginal cardiac orrenal reserves; (2) procure aliquots of mixed venous blood repeatedlyfor gasometric or biochemical analysis; (3) administer massive volumesof fluid or blood rapidly for resuscitation and ancilary purposes; (4)infuse intravenously, over long periods of time, hypertonic, acidic orkindred irritant solutions which would assuredly incite phlebosclerosiswere they not diluted right away in the faster stream of the centralvenous channels. Hyperalimentation or total parenteral nutritionformulas are foremost in this catagory. One or more of thosespecifications appertain to myriad clinical entities: hypovolemic shock,dehydration, cerebral edema; inanition; major trauma; serve hemorrhage;extensive bowel resection; gastrointestinal fistulas; certain cancersrequiring prolonged infusion of cytotoxic agents; continuous injectionof antibiotics in concentrated doses for treating infectiveendocarditis; and so forth.

While a preferred embodiment of the present invention has been describedso as to enable one skilled in the art to practice the technique of thepresent invention, the preceding description is intended to be exemplaryand should not be used to limit the scope of the invention. The scope ofthe invention should determined only be reference to the followingclaims.

What is claimed is:
 1. A kit for use in conjunction with a hypodermicsyringe for catheterizing a subject, said syringe having a needle with atip portion for insertion into said subject, said kit comprising:asubstantially cylindrical introducer means having a frustconical firstend and a generally planar opposite end and a bore extending throughsaid introducer, said bore having a diameter substantially equal to theouter diameter of said needle such that the introducer tightly engagessaid needle to create sealing engagement therebetween, and a slitextending the length of said introducer, said introducer being resilientsuch that the opposed walls of said slit are normally biased against oneanother to prevent the ingress of fluid into said bore, said introducerbeing removably positioned about said needle to expose said tip wherebysaid needle and introducer are easily insertable into said subject andsaid needle is longitudinally removable from said introducer afterinsertion; a guide wire for insertion into said introducer to a desiredlocation within said subject, said introducer being removable from saidwire along said slit; and a catheter having an outer diameter generallyequal to or greater than the outer diameter of said introducer, saidcatheter being received by said wire and threadable along said wire intosaid subject after said introducer has been removed from said wire alongsaid slit; said bore of said introducer being substantially smaller thanthe outer diameter of said catheter with said catheter being incapableof entering said bore; said wire being removable from said catheter whensaid catheter reaches said desired location.
 2. The kit of claim 1,wherein said wire is initially positioned in said catheter prior topassing said wire through said introducer.